THE USE OF C-3-SYMMETRICAL TRIPODAL LIGANDS IN CRYSTAL ENGINEERING

The use of chiral tripodal ligands in the assembly of non-centrosymmet ric crystal lattice is illustrated with the triamide ligand tris -(S)- (-)-(alpha)-methylbenzylcarbamoylmethyl]amine (H(3)1(S-mbz)). In the c rystal phase, this tripodal ligand assembles into C-3-symmetric chiral columns that are stabilized by hydrogen bonds and aryl-aryl interacti ons. Intercolumnar assembly is driven by the clustering of edge-to-fac e aryl and methyl-to-aryl interactions. Thrice deprotonation of H(3)1( S-mbz) and binding of an Ni(II)-F moiety also produces a non-centrosym metric lattice which is noteworthy for its six-fold symmetric open fra mework structure and the alignment of all the molecular Ni-F bonds in the lattice along the crystallographic c-axis. Crystal data: H(3)1(S-m bz) crystallizes in the rhombohedral system, space group R3 with cell dimensions a = b = 22.352(5) Angstrom, c = 4.882(1) Angstrom, alpha = beta = 90 degrees, gamma = 120 degrees, and Z = 3; [NEt4](2)[Ni1(S-mbz )(F] crystallizes in the hexagonal system, space group P6(3) with cell dimensions a = b = 12.0780(1) Angstrom, c = 18.1231 (1) Angstrom, alp ha = beta = 90 degrees, gamma = 120 degrees, and Z = 2. (C) 1998 Elsev ier Science S.A. All rights reserved.